The continuing clean-up of the underground storage tank at the Idyllwild Chevron site is one of 13 projects that have been transferred to the State Water Resources Control Board’s Santa Ana Regional board. The transfer was effective July 1.
Riverside County Department of Environmental Health is no longer contracting with the state to oversee these types of projects.
The transfer of oversight responsibility occurred just weeks after the county had approved a work plan for the local site. This work would have included two more off-site monitoring wells, seven soil gas-vapor probes and four borings to collect groundwater data.
Groundwater samples from March (only well no. 15 is tested every quarter) revealed decreasing methyl tertiary-butyl ether concentrations in all but one well, where the concentration was up “slightly,” according to the report. In June, the MTBE levels decreased for this well.
However, benzene, toluene and xylene concentrations were elevated in several wells, none of which were off-site.
These wells are all located on the station site and the concentrations may have been higher in March because the very wet winter raised the groundwater level of all of the monitoring wells.
One of the other 12 projects transferred to the SWRCB (Santa Ana) is located at the U.S. Forest Service’s Keenwild Ranger Station near Mountain Center. According to the county report, some remediation has started and more work will begin this month.